Injector.



UNTED STATES PATENT GFFCE,

RCHARD DAVID MLETCLFE AND JAMES CBOXON METCALFE, GF ROMnEY, ENGLAND.

INJECTQB.

Specification of Letters Patent.

rammen ocr. er, 191;.

Application filed .Tune 26. 1913. Serial No. 775,941.

To all lwhom it may concern Be it known that we, RICHARD DAvn) Mnr- CALFE and JAMES CnoXoN METCALFE, subjects ol? the King of Great Britain and lrelend, residing :it lnjector lVorlis, Romiley, in the county of Chester, England, have invented certain new and useful Improvements in Injectors, of which the following is a specification.

This invention relates to injectors and has for its object to provide an improved and simplilied combination and arrangement of parts for adapting an injector to work eliiciently and out-oniatically with both hot and cold feed waiter and high pressure steam.

Heretoore various arrangements ofi injectors have been proposed for regulating or controlling the overflow from the combining nozzle when the injector is starting and when it is working normally. For example, in the specification of our United States Pat ent No. 905206, we proposed to divide the overflow chamber into two compartments and to provide upon the one compartment a Jfree or unloaded overflow valve while the other compartment has a valve thereon loadek by the pressure in the injector delivery chamber. This arrangement, while quite satisfactory in operation, is relatively expensive to construct.

According to our present' invention, we provide a simple combination of parts which is economical to malte and which is etlicient in notion. The said combination comprises the provision iu an injector having,r a l'rec non-return flap arrangement. on th(` combiningi nozzle und an overflow passage or chair nel controlled by the pressure in the delivery chamber, of a springr adapted to oppose the pressure in the delivery chamber and so corogn'essed that. when the injector is starting', the overflow valve con be readily opened while said valve is held closed during nor-- mal working` Referring to the accompanying:Y sheet| ot explanatory drawings: Figure l is a sectional plan view, Fig Q a sectional elevation and Fig. 3 n cross section on the line A B of Fig. l showing an injector constructed in accordance with our invention.

The same reference letters in the different indicate the saine parts.

The injector comprises e steam nozzle a, a water inlet connection l, a combining nozzle o in which the steam and water unite, and o delivery nozzle d in which the kinetic energy of the jet is converted into pressure. energy. The water from said nozzle passes through the delivery chamber e to the outlet f.

Vhen the injector is starting, steam ontering by the nozzle issues into the nozzle c and by an ejector action draws water in from the connection o. It will be readily understood that no delivery cnn take place from the injector' until the stoom jet is condensed by the Jreed water from c which is then given a high velocity. lt is therefore necessary to provide that until the jet in the combining nozzle has suilicien'tvelocity and the proper density' to etl'eet delivery against the pressure in thc boiler or vessel being fed, there shall be a free escape from the combining nozzle to the overflow passage g. But a further condition also has to be satisfied in regard to the overflow from the combining nozzle, for it is found that if the steam pressure be high and the initial feed water temperature also high, there may be a pressure considerably above atmospheric in the overflow chamber when the injector is working normally. A free escape of overflow such ns is required when the injector is storting would not` therefore be of service when the injector is working normally.

To allow of the free escape from the combining nozzle, we. provide not only a gap L between the combining and delivery nozzles but also a flap The pressure et the gap h is during! normal working of the injector always greater than et the point where the flap z' is situated, so ,that lby closing: the overflow chamber f we can cause the said excess of pressure to hold the flop closed, when the combining nozzle presents an unbroken channel for the flow of the steam and water during mixing'.

As already explained', thi` overflow from the combining nozzle should notbe restricted until the liet is ahlc to deliver' into telic vessel being; fed. lt isy however. found in practice that even at starting when no delivery is takingV place iroin the injector (out steam only issuing into the combining nozzle) a considerable pressure may exist in thc delivery chamber, such pressure gradually risboiler being fed. lt will be understood, therefore, that merely to load the overflow valve lc by tbe pressure in the chamber e would cause a tlirottling of the overflow from the combining nozzle at starting and therefore impair the liftingr automatic restarting powers of the appliance. To oven come this objection (which in our previous patent was obviated by the. division of tbe overflow chamber into two compartments, one of which had a free or unloaded valve l thereon) we provide a. spring m actingrl on the lever n to oppose the pressure in the delivery chainber acting on the plunger o. The lever n loads the valve c through the Ymedium of the strut 7).

The strength of the spring m must be sufficient to overcome the pressure which is created at starting or restarting in the delivery Chamber as before explained and the inertia and friction of the plunger o, lever v'n and strut p so'tliat no load is placed upon the overflow valve k until normal working conditions are established. When working with low pressure steam, however, the spring pressure may be greater than the delivery pressure but under such conditions the overflow pressure will during normal working be` less than atmospheric. TWe therefore make the 'overflow valve .1c entirely independentvo'fthe automatic loading' means and such that. italways tends to rest upon is seat and so, seal the overflow passage. It will be seen that the valve 7c is a flap or hanging valve pivoted about the pin k1.

The operation of the injector with hot feed warer andhigli pressure steam is as follows: `Al; starting the reduced pressure .in

vthe delivery chamber e is effectually resisted by the spring mand the overflow valve 7c is free to open. The steam issuing into the combining nozzle therefore forces open the flap i and issues into the overflow chamber j and thence .through the overflow pipe g past the valve `When, however, the injector commences toY work normally, the pressure in tliedelivery chamber rises above the pressure in tbe overflow chamber together with the pressure exerted by the spring; m and so loads the valve and seals the overflow chamber, thus prevcl'iizing file overflow which would otherwise take place due to the pressure in the overllow chamber being greater than atmospheric, lrnrnediately tlne valve closes, the pressure at the gap la being greater lthan al', the flap e', due to the higher temperature of the jet at that point, acts upon and closes the liap so giving an unbroken nozzle for ille flow of the jet during mixing.

Our improved injector is economical to make and is elli/cient in action.

Having now described our invention what we claim new and desire no secure by Letn ters Patent is :A

l. ln injectors, in combination, a stean'i nozzle, a combining nozzle, a delivery nozzle, an overflow chamber, a delivery chamber, a water inlet, an overllow gap between the eorrfnining,r and delivery nozzles, freely open'- ing and closing overflow means upon the combining nozzle; an overflow valve, inea-ns loading said overflow valve bv the pressure in the injector delivery chamber, and means partly neutralizing saidY pressure, as sel', forth.

2. ln injectors, in combination, a steam nozzle, a combining nozzle, a delivery nozzle, an overflow chamber, a delivery chamber, a water. inlet, an overflow gap between the combining and delivery nozzles, freely opening and closing overflow means upon the combining nozzle, a free overflow valve upon the overflow chamber, a plunger loaded by the pressure in the delivery chamber, a lever and a rod conveying the load upon said plunger to said overflow valve and means preventing the loading of said overflow valve luntil the plunger load exceeds a predetermined amount, set forthv 3. ln. injectors, in combination, a steam nozzle, a combining nozzle, a delivery noz; Zle, an overflow cl'mxnber, a delivery chaniber, a water inlet, an overflow ,crap between the combining and delivery nozzles, freely opening and closing overflow means upon the combining nozzle, a free overflow valve upon the overflow chamber, a plunger loaded by the pressure in the delivery chamber, a lever and a rod conveying the load .upon Said plunger lo said overflow valve, and n spring preventing the loading of said overflow valve until the injector delivery pressure overcomes the spring resistance, as sel; forth. y

In testimony whereof we have signed our names to this specification in the presence of wo subscribing witnesses.

RICHARD DAVID METCALFE. JAMES CROXON METCALFE. Witnesses:

ARTHUR HUGHES, ERNoLn SIMPSON Mossnnr.

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